1. Field of the Invention
The invention relates to an image processing device for the real-time processing and recognition of an image consisting of a two-dimensional array of digitized pixels, said device including:
a. receiving means for receiving the pixels in order to form therefrom a first bit stream in which each bit represents a pizel;
b. a sub-sampling circuit which includes a control input for forming a second bit stream from the first bit stream, under the control of a pitch-increasing control signal on the control input, and for selectively increasing the pitch of a secondary raster period thereof with respect to a raster of pixels received;
c. a buffer which is line-wise fed by the sub-sampling circuit in order to effect temporary storage of the second bit stream and to present the information of a column of pixels in parallel on an output;
d. a correlation circuit which is fed by the buffer in order to compare the pixels of a number of successively received columns with corresponding reference pixels, a masking circuit indicating each pixel-wise comparison as being relevant/irrelevant;
e. clock means for controlling the sub-sampling circuit, the buffer, the correlation circuit and the selection/processing circuit in mutual synchronism and for controlling the receiving means isochronously with respect thereto.
2. Prior Art
Such a device is known from U.S. Pat. No. 4,200,861. The known device first performs a coarse-pitched sampling operation in order to determine the position of a desired part of the image. Subsequently, a fine-pitched sampling operation is performed in order to safeguard the position/presence of this part of the image. The known device involves two steps, so that it does not operate on a real-time basis.